Conventional projection arrangements, such as DLP projectors, for example, include a color wheel and a discharge lamp, such as UHP lamps, for example, for illuminating the color wheel. In this case, the color wheel rotates at a predefined, e.g. constant, frequency. In this case, the lamps are operated with alternating current and driven by a ballast. The two electrodes of the discharge lamp undergo polarity reversal during a commutation of the lamp current. With adaptation of the operating frequency of the discharge lamp to the color wheel, the ballast provides a suitable lamp current having a specific wave form having a commutation scheme.
Furthermore, such projectors have an integrator. The latter is designed to mix the radiation emitted by different points of the arc between the electrodes during the operation of the discharge lamp by multiple reflection such that non-uniformities in the light level of the projected image are compensated for. Nevertheless, under certain circumstances, visible oscillations in the light level of the projected image occur, e.g. if, for cost reasons, the projector hardware cannot be optimized further, such as by the choice of an integrator which is longer in relation to its entrance area and is thus more effective.